Clevenger et al., U.S. Pat. No. 6,448,173, issued Sep. 10, 2002, discloses a dual damascene process capable of reliably producing aluminum interconnects that exhibit improved electromigration characteristics over aluminum interconnects produced by conventional RIE techniques. The dual damascene process relies on a PVD-Ti/CVD-TiN barrier layer that produces aluminum lines that exhibit significantly reduced saturation resistance levels and/or suppressed electromigration, particularly in lines longer than 100 micrometers.
Bothra, U.S. Pat. No. 6,297,557, issued Oct. 2, 2001, discloses an aluminum filled via hole for use in a semiconductor interconnect structure. The aluminum filled via hole in a semiconductor interconnect structure includes a first patterned metallization layer lying over a first dielectric layer. A second dielectric layer overlying the first patterned metallization layer and the first dielectric layer. An aluminum filled via hole defined through the second dielectric layer and in contact with the first patterned metallization layer. The aluminum filled via hole has an electromigration barrier cap over a top most portion of the aluminum filled via hole that is substantially level with the second dielectric layer. The electromigration barrier cap has a thickness of between about 500 angstroms and about 2500 angstroms. An electromigration barrier layer is deposited over the second dielectric layer and within the recess gap. The electromigration barrier is preferably a titanium tungsten, a tungsten, or tungsten silicide layer deposited using a sputter process or CVD process to a thickness of about 1000 angstroms to about 300 angstroms.
It is heretofore been known to combine CVD aluminum technology with an overlayer of PVD aluminum deposited to fill small geometries.
Heretofore it has also been known to use CVD aluminum plugs to deposit the plug fill and interconnect in the same deposition step. Chemical vapor deposition of aluminum plugs using MOCVD precursors such as dimethyl aluminum hydride has been known to offer a means for forming plugs and interconnects with high quality aluminum films at process temperatures below 200° C.
Heretofore it has also been known to utilize an unsequential deposition of thin CVD aluminum film and PVD Al (Cu). The chemical vapor deposition aluminum is deposited at low temperatures using dimethyl-aluminum hydride.
Chio et al., U.S. Pat. No. 5,629,238, issued May 13, 1997, discloses a method of forming a conductive line using a fluorine doped oxide layer as an insulating layer between conductive lines. The method comprises the steps of: (a) forming a fluorine doped oxide layer on a semiconductor substrate on which a lower structure is formed; (b) etching the oxide layer of the region where a conductive line is to be formed, followed by forming a trench; (c) forming an insulating layer over the overall surface of the resultant substrate; (d) depositing conductive material on the resulting substrate; and (e) etching back the conductive material so that the conductive material is left on the trench only, thereby forming a conductive line. The conductive line is formed of aluminum-containing material and the insulating layer is formed of silicon dioxide. The insulating layer is interposed between the fluorine doped oxide layer and the aluminum-containing conductive line and the conductive line is free from corrosion.
Lee et al., U.S. Pat. No. 5,843,843, issued Dec. 1, 1998, discloses metal wiring structures for integrated circuits including a seed layer formed on an integrated circuit substrate and a wetting layer formed on the seed layer opposite the integrated circuit substrate. The metal wiring layer is formed on the wetting layer opposite the seed layer. The seed layer and the metal wiring layer have the same crystal orientation. In a preferred embodiment, the seed layer is an aluminum layer having a (111) crystal orientation and the metal wiring layer has an aluminum having (111) crystal orientation. The metal wiring layer may be aluminum or an aluminum alloy. The wetting layer preferably is titanium.
The present invention provides alternatives to the prior art.